Reuse Field catelog merge

Hi ,

I am using Field catelog merge,

DATA: lt_scr TYPE STANDARD TABLE OF /table WITH HEADER LINE,

SELECT * FROM table INTO TABLE lt_scr up to 5 rows.

CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'

EXPORTING

I_PROGRAM_NAME = sy-repid

I_INTERNAL_TABNAME = 'LT_SCR'

I_INCLNAME = sy-repid

CHANGING

CT_FIELDCAT = LT_FCAT

EXCEPTIONS

INCONSISTENT_INTERFACE = 1

PROGRAM_ERROR = 2

OTHERS = 3.

and when I go in debug mode, this LT_FCAT is blank.

Any ideas plz.